共查询到20条相似文献,搜索用时 83 毫秒
1.
生长激素释放肽(ghrelin)是在大鼠和人胃内发现的,是一种生长激素促分泌素受体(growth hormone secretagogue receptor,GHSR)的内源性配体.ghrelin与位于垂体、下丘脑的GHSR结合后,具有促进生长激素释放、增加食欲、调节消化系统功能和能量代谢等作用.本文对ghrelin的... 相似文献
2.
畜禽生长激素释放因子(GRF)的研究进展 总被引:4,自引:0,他引:4
生长激素释放因子(growth hormone- releasing factor,GRF)又称生长激素释放激素(growth hormone- releasinghorm one,GHRH) ,是存在于脊椎动物体内的一种生物活性多肽,由下丘脑合成并分泌,对脊椎动物的生长、发育及代谢调控起着极其重要的作用。其主要功能是,作为脑垂体生长激素(growth hormone,GH)的正性调控因子,能特异地诱导生长激素的合成与分泌,增高动物机体内的GH水平。而生长激素释放抑制因子(som atostain,SS)则抑制GH的合成与释放。GRF与其伴随的SS低谷诱发形成GH的分泌峰,峰的高度取决于GRF的强度及垂体对GRF的敏感… 相似文献
3.
此试验研究注射促生长激素释放肽(GHRP-2)20μg/kg体重对猪生长、养分消化率和胴体组成及特性的影响。采用单因子试验设计,将10头杜长大三元杂种去势公猪(约64kg),分为对照组和试验组2个处理,每个处理5个重复,每个重复1头猪。2个处理分别为:(1)空白对照组,隔天注射和试验组相等剂量的生理盐水;(2)试验组,隔天肌肉注射GHRP-220μg/kg体重,共注射14天。试验期为4周,期间以周为单位记录增重和采食量,到28天时结束饲养试验,对所有猪进行放血屠宰。结果表明,试验组全期生产性能与对照组相比,注射GHRP-220μg/kg体重使日增重增加14.15%(P<0.05),料重比下降11.92%(P<0.05),而日采食量(kg)几乎相等(分别为3.19±0.16,3.2±0.2)。注射GHRP-220μg/kg体重对胴体组成没有显著的影响(P>0.05);对养分表观消化率影响差异不显著(P>0.05),蛋白质表观利用率提高7.46%(P<0.05);提高了血钙(P<0.05)和极低密度胆固醇水平(P<0.01),降低了甘油三脂水平(P<0.01)和乳酸脱氢酶活力(P<0.05)。结论,GHRP-2可以提高猪的生产性能,但在改善胴体组成上效果不明显。 相似文献
4.
Ghrelin是从鼠和人的胃中分离得到的一种生长激素释放激素受体的天然的内源性配体,它由28个氨基酸残基组成,且氮端第三位丝氨酸发生了辛酰基化,Ghrelin具有广泛的生物学功能,包括调节能量平衡、调节胃肠功能、调节生长激素释放及调控动物采食等等,对Ghrelin的研究具有重要的理论意义和广阔的应用前景。 相似文献
5.
Ghrelin生物学功能的研究进展 总被引:1,自引:0,他引:1
Ghrelin是一种在大鼠和人胃内新发现的生长激素促分泌素受体(GHS-R)的内源性配基,有28个氨基酸,起促生长激素释放作用。当Ghrelin与位于垂体和下丘脑的GHS-R结合后,产生一系列生物学效应。本文从生长激素释放、机体生长发育、食欲和采食量、能量代谢、胃酸分泌等方面综述了Ghrelin的生物学功能,并初步探讨其在畜牧业上的应用前景。 相似文献
6.
7.
生长激素释放肽(Ghrelin)是一种在动物体内广泛存在的生长激素促分泌素受体(GHSR)的内源性配体, Ghrelin与位于下丘脑的GHSR结合后,具有促进生长激素释放、增加食欲、调节消化系统功能及能量代谢等作用。文章就Ghrelin的结构、分布、生物学效应及在畜牧业上的应用前景等方面进行综述,以期促进Ghrelin的进一步深入研究。 相似文献
8.
生长激素释放因子(growth hormone-releasing factor,GRF)主要是由下丘脑弓状核的神经细胞分泌产生的,是一种蛋白类激素,不同动物物种的GRF有所不同.成熟的GHRH一般含有40~44个氨基酸残基,是生长激素的正性调控因子,可与生长激素释放抑制因子(somatostain,SS)共同调节生长激素(growth hormone,GH)的分泌.GRF能特异性地增加生长激素的mRNA,从而增加生长激素的生成,达到加快核酸和蛋白质的合成,减少脂肪沉积,进而影响动物的生产性能. 相似文献
9.
生长激素释放肽-6缓释微球的制备及其对动物生长的影响 总被引:3,自引:0,他引:3
以生物降解材料乳酸乙醇酸共聚物(PLGA,LA-GA 8515)为载体,采用复乳-液中蒸发法制备含生长激素释放肽-6的乳酸乙醇酸共聚物微球,并通过体外药物释放试验评价载药微球的释药特征.结果得到收率、粒径大小和分布及含药量均满意的微球,其中包封率为100%,平均体积径为3.45μm,收率为79%.在37℃、pH7.0的生理等渗缓冲液中,首日释药19.19%,其后以平均日释药3.23%的速度释药25 d.小鼠肌肉注射微球30 d后,累积增重比注射生长激素释放肽-6、生理盐水分别高22.56%(P<0.05)和53.17%(P<0.01).结果表明,生长激素释放肽-6乳酸乙醇酸共聚物微球有望发展成为新型长效制剂. 相似文献
10.
11.
12.
神经生长因子的研究进展 总被引:3,自引:0,他引:3
1 NGF及其受体的结构NGF是一种由三种不同类型的蛋白质组成的复合物,其分子量为1 4 0 0 0 0左右。其三种蛋白质分别为一个β亚单位和两个α亚单位以及两个γ亚单位以非共价键结合。其组合比例为α2 βγ2 。此外,该分子还包括了2个锌指,增加了复合物的稳定性。α亚单位的分子量为2 6 50 0 ,作用不明。γ亚单位分子量为2 6 0 0 0 ,有脂酶活性,能将无活性的γ亚单位转化为有活性的γ亚单位。先前的研究显示,β-NGF是一种二聚体分子,其单链含有1 1 8个氨基酸残基。近年的研究发现β-NGF的三维空间结构,其单位是由三对反向平行的β股构成… 相似文献
13.
14.
15.
疫苗佐剂是使疫苗免疫原性充分发挥的工具,目前动物疫苗佐剂主要以铝盐佐剂和油乳佐剂为主。近年来基因重组疫苗和亚单位疫苗发展迅猛,而这些新型疫苗与传统疫苗相比免疫原性较弱,这就对佐剂提出了更高的要求。当前针对佐剂的研究层出不穷,部分佐剂如MF59、AS01、AS03等已经在人用疫苗中成功应用,但应用于动物疫苗还有技术难题需要攻破。蜂胶佐剂目前在动物疫苗中应用较广,且已经占有了一定的市场份额。为充分比较现有新型疫苗佐剂的优缺点,为后续疫苗佐剂的研究提供参考,就目前广泛研究的新型动物疫苗佐剂进行综述。 相似文献
16.
Sixteen pregnant Holstein heifers (430kg) were used to determine the effect of long-term administration of a bovine growth hormone (bGH) made by recombinant DNA technology on the ability of a bolus injection of a growth hormone-releasing hormone analog (Ac-His-1, D-Ala-2, Nle-27, GHRH(1-29 NH2) to increase serum GH. Eight heifers received a daily intramuscular injection of bGH (50 mg/day) for 5 months while the other half received a daily injection of physiological saline (control) over the same period. On the last day of bGH treatment and 1, 5, 10 and 25 days after the cessation of bGH treatment, five heifers from each group were challenged with GHRH analog and the response to this releasing hormone analog was measured. Basal GH concentrations were elevated on the last day of treatment in bGH-treated heifers and declined to concentrations similar to control heifers by 1 day after cessation of treatment. Response to GHRH analog was impaired by bGH during the last day of treatment and one day later. Responsiveness returned to a level similar to controls by 5 days after the end of bGH treatment. Response to GHRH analog was lessened during the period of bGH treatment but there were no long term effects on the animals' ability to respond to the releasing hormone. 相似文献
17.
Stimulation of pig growth performance by porcine growth hormone and growth hormone-releasing factor 总被引:10,自引:0,他引:10
T D Etherton J P Wiggins C S Chung C M Evock J F Rebhun P E Walton 《Journal of animal science》1986,63(5):1389-1399
The current study was undertaken to determine the effects of human growth hormone-releasing factor [hpGRF-(1-44)-NH2] on growth performance in pigs and whether this response was comparable to exogenous porcine growth hormone (pGH) treatment. Preliminary studies were conducted to determine if GRF increased plasma GH concentration after iv and im injection and the nature of the dose response. Growth hormone-releasing factor stimulated the release of pGH in a dose-dependent fashion, although the individual responses varied widely among pigs. The results from the im study were used to determine the dose of GRF to use for a 30-d growth trial. Thirty-six Yorkshire-Duroc barrows (initial wt 50 kg) were randomly allotted to one of three experimental groups (C = control, GRF and pGH). Pigs were treated daily with 30 micrograms of GRF/kg body weight by im injection in the neck. Pigs treated with pGH were also given 30 micrograms/kg body weight by im injection. Growth rate was increased 10% by pGH vs C pigs (P less than .05). Growth rate was not affected by GRF; however, hot and chilled carcass weights were increased 5% vs C pigs (P less than .05). On an absolute basis, adipose tissue mass was unaffected by pGH or GRF. Carcass lipid (percent of soft-tissue mass) was decreased 13% by GRF (P less than .05) and 18% by pGH (P less than .05). Muscle mass was significantly increased by pGH but not by GRF. There was a trend for feed efficiency to be improved by GRF; however, this was not different from control pigs. In contrast, pGH increased feed efficiency 19% vs control pigs (P less than .05). Chronic administration of GRF increased anterior pituitary weight but did not affect pituitary GH content or concentration. When blood was taken 3 h post-injection, both GRF- and pGH-treated pigs had lower blood-urea nitrogen concentrations. Serum glucose was significantly elevated by both GRF and pGH treatment. This was associated with an elevation in serum insulin. These results indicate that increasing the GH concentration in blood by either exogenous GH or GRF enhances growth performance. The effects of pGH were more marked than for GRF. Further studies are needed to determine the optimal dose of GRF to administer in growth trials and the appropriate pattern of GRF administration in order to determine whether GRF will enhance pig growth performance to the extent that exogenous pGH does. 相似文献
18.
19.
20.
Biological potencies of three 29 amino acid growth hormone-releasing hormone analogs (GHRH[1-29]) were determined in the bovine and compared to synthetic human GHRH (44 amino acids; hGHRH[1-44]NH2) for their ability to increase serum growth hormone (GH) concentrations. Four prepubertal Holstein heifers (179 +/- 10 kg) received hGHRH(1-44)NH2 or analogs (D-Ala2, Nle27, Agm29 GHRH[1-29], [JG-73]; D-N-MeAla2, Nle27, Agm29 GHRH[1-29], [JG-75]; and desamino-Tyr1, D-Ala2, Nle27, Agm29 GHRH[1-29], [JG-77]) at the following doses: 0, 6.25, 25, 100 and 400 micrograms/animal. All treatment-dose combinations were administered to each heifer with at least a 1-d interval between treatments. Sixteen blood samples were collected via jugular cannulas 20 min before and up to 6 h after treatment injection. There was a linear dose-dependent GH release in response to hGHRH(1-44)NH2 and the three analogs. Growth hormone peak amplitudes for the three analogs were similar to those observed after administration of the hGHRH(1-44)NH2 (P greater than .05). However, when total area under the GH response curves for each treatment was averaged over all the doses, JG-73 stimulated greater GH release than hGHRH(1-44)NH2 (P less than .05) Heifers injected with the 400-microgram dose of hGHRH(1-44)NH2 or the three analogs showed a primary release of GH followed by a secondary release 1 h later. At all other doses, only a primary GH release was observed.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献